Extrusion Based 3D Printing of Sustainable Biocomposites from Biocarbon and Poly(trimethylene terephthalate).

Three-dimensional (3D) printing manufactures intricate computer aided designs without time and resource spent for mold creation. The rapid growth of this industry has led to its extensive use in the automotive, biomedical, and electrical industries. In this work, biobased poly(trimethylene terephthalate) (PTT) blends were combined with pyrolyzed biomass to create sustainable and novel printing materials. The Miscanthus biocarbon (BC), generated from pyrolysis at 650 °C, was combined with an optimized PTT blend at 5 and 10 wt % to generate filaments for extrusion 3D printing. Samples were printed and analyzed according to their thermal, mechanical, and morphological properties. Although there were no significant differences seen in the mechanical properties between the two BC composites, the optimal quantity of BC was 5 wt % based upon dimensional stability, ease of printing, and surface finish. These printable materials show great promise for implementation into customizable, non-structural components in the electrical and automotive industries.

Fabrication of New Demulsifiers Employing the Waste Polyethylene Terephthalate and their Demulsification Efficiency for Heavy Crude Oil Emulsions.

Two novel amphiphilic polyethylene amine terephthalate have been prepared via the glycolsis of polyethylene terephthalate (PET). The product, bis (2-hydroxyethyl terephthalate) (BHET), was converted to the corresponding dialkyl halide, bis(2-chloroethyl) terephthalate (BCET), using thionyl chloride (TC). This dialkyl compound was used for alkylation of dodecyl amine (DOA) and tetraethylenepentamine (TEPA) or pentaethylenehexamine (PEHA) to form the corresponding polyethylene amine terephthalate, i.e., DOAT and DOAP, respectively. Their chemical structure, surface tension, interfacial tension (IFT), and dynamic light scattering (DLS) were determined using different techniques. The efficiency of the prepared polyethylene amine terephthalate to demulsify water in heavy crude (W/O) emulsions was also determined and found to increase as their concentrations increased. Moreover, DOAT showed faster and higher efficiency, and cleaner separation than DOAP.

Favorable combination of foldability and toughness of transparent cellulose nanofibril films by a PET fiber-reinforced strategy.

Transparent cellulose nanofibril (CNF) films have been considered a promising sustainable alternative for nonrenewable and nonbiodegradable petroleum-based plastic films. However, their relatively low toughness and poor folding endurance are two remaining challenges for commercial application. In this work, inspired by fiber-reinforced polymer, a transparent CNF film with favorable combination of toughness and folding endurance is demonstrated by a facile and scalable polyethylene terephthalate (PET) fiber-reinforced strategy. The as-prepared PET fiber-reinforced CNF film not only exhibits a maximum average toughness of 13.7 ± 2.4 MJ/m3 that is nearly 4 times stronger than that of pure CNF film (3.7 ± 1.1 MJ/m3), but also presents superior bending flexibility with a folding endurance of over 104 times that is an order of magnitude higher than that of pure CNF film (~4 × 103 times). Moreover, its underlying principle for the enhanced toughness and foldability is explored. This work provides a facile strategy to prepare tough yet foldable CNF film and could promote its industrial uses in the fields of energy storage devices, packaging, and electronic devices.

Synthesis of novel multi-hydroxyl N-halamine precursors based on barbituric acid and their applications in antibacterial poly(ethylene terephthalate) (PET) materials.

Two novel multi-hydroxyl N-halamine precursors were successfully synthesized in a green and facile way via Knoevenagel condensation reaction between barbituric acid and an aldehyde (citral or cinnamaldehyde), followed by a hydroxylation reaction with hydrogen peroxide. 1H-NMR and FT-IR spectral analyses confirmed their formation. Through the melt-blending process, the multi-hydroxyl derivatives of barbituric acid were introduced via transesterification into poly(ethylene terephthalate) (PET) at 265 °C in a rheometer. The crystallization behaviors of the modified PET samples were investigated using X-ray diffraction (XRD), differential scanning calorimetry (DSC), and polarized optical microscopy (POM) analyses. The results showed that the crystallization temperature and crystallization rate of PET were significantly improved upon the introduction of the precursor. Meanwhile, the relative crystallinity of the modified PET samples increased with an increase in the dosage of the N-halamine precursor. After the treatment with sodium hypochlorite solution, the PET surfaces modified with N-halamine derivatives would impart powerful antibacterial properties and achieve 100% killing of Staphylococcus aureus (ATCC 6538) and Escherichia coli (CMCC44103) cells within 30 min. Therefore, the multi-hydroxyl N-halamine precursors exhibit great potential as bifunctional additives (nucleating and antibacterial agents) in the manufacturing of functional PET materials.

Bioinert Control of Zwitterionic Poly(ethylene terephtalate) Fibrous Membranes.

Poly(ethylene terephtalate) (PET)-based materials face general biofouling issues that we addressed by grafting a copolymer of glycidyl methacrylate and sulfobetaine methacrylate, poly(GMA- r-SBMA). The grafting procedure involved a dip-coating step followed by UV-exposure and led to successful grafting of the copolymer as evidenced by X-ray photoelectron spectroscopy and zeta potential measurements. It did not modify the pore size nor the porosity of the PET membranes. In addition, their surface hydrophilicity was considerably improved, with a water contact angle falling to 30° in less than 20 s and 0° in less than 1 min. The effect of copolymer concentration in the coating bath (dip-coating procedure) and UV exposure time (UV step) were scrutinized during biofouling studies involving several bacteria such as Escherichia coli and Stenotrophomonas maltophilia, but also whole blood and HT1080 fibroblasts cells. The results indicate that if all conditions led to improved biofouling mitigation, due to the efficiency of the zwitterionic copolymer and grafting procedure, a higher concentration (15 mg/mL) and longer UV exposure time (at least 10 min) enhanced the grafting density which reflected on the biofouling results and permitted a better general biofouling control regardless of the nature of the biofoulant (bacteria, blood cells, fibroblasts).

Morphological Analysis of Biocompatibility of Autologous Bone Marrow Mononuclear Cells with Synthetic Polyethylene Terephthalate Scaffold.

We studied the properties of a tissue-engineered trachea consisting of a polyethylene terephthalate scaffold populated with autologous bone marrow mononuclear cells. The tissue-engineered constructs were obtained before surgery, during the postoperative period, and during autopsy. Cytomorphological analysis during the postoperative period showed the presence of mesenchymal stem cells on the inner surface of the implant on day 3 after surgery and cells of the respiratory epithelium on day 10-14. In autopsy samples, single epithelial cells, endothelial cells, and basal cells were found. Biocompatibility of the tissue-engineered trachea with autologous mononuclear cells of the patient was demonstrated.

Design of hemocompatible and antifouling PET sheets with synergistic zwitterionic surfaces.

Zwitterionic surface has been proven to be a good candidate for improving hemocompatible and antibiofouling properties. However, it can only passively repel the adsorption of microbes and is unable to kill the adherent or trapped microbes. The purpose of our study is to develop a facile method based on synergy "repel and kill" strategy and prepare dual antifouling and antibacterial surface. Herein, the poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) was first constructed via surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (ARGET-ATRP) method, followed by partial quaternization in order to form polycarboxybetaine and polysulfobetaine. The conversion rates of PDMAEMA to polyzwitterions were evaluated by X-ray photoelectron spectroscopy analysis (XPS). Surface characterizations by ATR-FTIR, XPS, and AFM demonstrated that zwitterionic polymer brushes were successfully grafted. The remained PDMAEMA(weak cationic) and formed zwitterions(neutral) endowed the surface with the synergetic antibacterial and antifouling properties. The resulting PET sheets showed outstanding antifouling property featured by the reduced adhesion of 3T3 fibroblast cells and E. coli. Additionally, these sheets displayed excellent hemocompatibility such as non-cytotoxicity, repelled protein adsorption, reduced platelet adhesion, and prolonged blood blotting time. These synergistic surfaces with neutral zwitterions and weak cations are promising for biomedical applications.

Development of silver nanoparticle loaded antibacterial polymer mesh using plasma polymerization process.

Plasma polymerized polyacrylic acid (PPAA) was deposited on a polymer substrate, namely polyethylene terephthalate (PET) mesh, for entrapment of silver nanoparticle (Ag-NP) in order to achieve antibacterial property to the material. Carboxylic groups of PPAA act as anchor as well as capping and stabilizing agents for Ag-NPs synthesized by chemical reduction method using NaBH(4) as a reducing agent. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), and water contact angle analysis were used to characterize the PPAA coatings. The Ag-NPs loaded polymer samples were characterized by UV-visible spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray, and XPS techniques. XPS analysis showed ~1.0 at.% loading of Ag-NPs on to the PPAA-PET-mesh, which was composed of 79% zero-valent (Ag°) and 21% oxidized nano-Ag (Ag(+) ). The plasma processed PET meshes samples were tested for antibacterial activity against two bacterial strains, namely Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative). Qualitative and quantitative tests showed that silver containing PPAA-PET meshes exhibit excellent antibacterial property against the tested bacteria with percent reduction of bacterial concentration >99%, compared to the untreated PET mesh.

All-optical full-color displays using polymer nanofibers.

We report a number of crossed nanofiber structures for full-color micro/nanodisplays, which were formed by assembling flexible poly(trimethylene terephthalate) (PTT) nanofibers under an optical microscope with the assistance of micromanipulators. The color pixels of the displays consist of micro/nanometer sized color spots in a radius of 300-1500 nm, which were realized through crossed junctions of the PTT nanofibers. The colors of the spots were tuned by changing the power ratios of the launched red, green, and blue lights. We further present a new way to develop white light illumination by combination of red, green, and blue lights with assembly techniques and low production costs.

Polyethylene terephthalate may yield endocrine disruptors.

BACKGROUND: Recent reports suggest that endocrine disruptors may leach into the contents of bottles made from polyethylene terephthalate (PET). PET is the main ingredient in most clear plastic containers used for beverages and condiments worldwide and has previously been generally assumed not to be a source of endocrine disruptors. OBJECTIVE: I begin by considering evidence that bottles made from PET may leach various phthalates that have been putatively identified as endocrine disruptors. I also consider evidence that leaching of antimony from PET containers may lead to endocrine-disrupting effects. DISCUSSION: The contents of the PET bottle, and the temperature at which it is stored, both appear to influence the rate and magnitude of leaching. Endocrine disruptors other than phthalates, specifically antimony, may also contribute to the endocrine-disrupting effect of water from PET containers. CONCLUSIONS: More research is needed in order to clarify the mechanisms whereby beverages and condiments in PET containers may be contaminated by endocrine-disrupting chemicals.

Improvement of the hemocompatibility of PET surfaces using different sulphated polysaccharides as coating materials.

In this study, sulphated polysaccharides were investigated in respect to their blood compatibility properties (hemocompatibility). Pure chitosan was treated with sulphating agents such as SO(3)/pyridine complex and chlorosulfonic acid (HClSO(3)) to obtain 3,6-O-sulfochitosan with low and high concentration of sulfur. These synthetically derived materials and the commercially available sulphated polysaccharides heparin and dextran sulfate, both with high concentrations of sulfur, were coated onto PET foils to act as surfaces with strong antithrombotic activity. This treatment should lead to better blood compatibility properties of PET materials for medical applications. To examine this, the optimized free hemoglobin method was applied to determine the antithrombotic activity of these surfaces. Glass as the standard thrombotic surface and a heparin-coated PET surface as a surface well-known for its strong antithrombotic activity were used as internal references. The experiments showed that dextran sulfate and sulphated chitosan with high concentrations of sulfur demonstrated the same antithrombotic activity as heparin over the whole period of measurement time. In addition, a relationship between the sulfur concentration in these sulphated polysaccharides and their blood compatibility properties can be demonstrated in this article.

Poly(ethylene terephthalate)/hydroxyapatite biomaterials: preparation, characterization, and in vitro bioactivity.

Poly(ethylene terephthalate)/hydroxyapatite (PET/HAp) composites were prepared by mixing HAp powder with a mixture solution of cyclic oligo(ethylene terephthalate) (C-OET) and dibutyl tinoxide catalyst in dichrolomethane, and then shaping the precomposites in cylindrical pellets. The C-OET in the precomposites was ring-opening polymerized (ROP) to PET under vacuum at 250 degrees C for 24 h. The PET/HAp composites were formulated with HAp to PET ratios of 60:40 (H6P4) and 50:50 (H5P5). The ROP-PET in the composites was present as a thin-layer coating on the HAp grains and evenly distributed throughout the samples. Compressive strength of the PET/HAp composites was significantly increased from 8 MPa of the H10P0 to 17 and 29 MPa for H6P4 and H5P5, respectively. In vitro bioactivity of the PET/HAp composites was studied by soaking in simulated body fluid (SBF) at 36.5 degrees C for 7-28 days. After prolonged soaking, the HAp nanocrystals precipitated from the SBF solution and formed as a layer of globular aggregates, coated on the composite surfaces. The H6P4 composite showed faster formation rate of nano-HAp than the H5P5 composite, indicating that the bioactivity of PET/HAp composites depended on the amount of HAp.

Characterization of surface modified polyester fabric.

Woven polyethylene terephthalate (PET) fabric has been used in the construction of vascular grafts and sewing ring of prosthetic heart valves. In an effort to improve haemocompatibility and tissue response to PET fabric, a fluoropolymer, polyvinylidine fluoride (PVDF), was coated on PET fabric by dip coating technique. The coating was found to be uniform and no significant changes occurred on physical properties such as water permeability and burst strength. Cell culture cytotoxicity studies showed that coated PET was non-cytotoxic to L929 fibroblast cell lines. In vitro studies revealed that coating improved haemocompatibility of PET fabric material. Coating reduced platelet consumption of PET fabric by 50%. Upon surface modification leukocyte consumption of PET was reduced by 24%. About 60% reduction in partial thromboplastin time (PTT) observed when PET was coated with PVDF. Results of endothelial cell proliferation studies showed that surface coating did not have any substantial impact on cell proliferation. Overall results indicate that coating has potential to improve haemocompatibility of PET fabric without affecting its mechanical performance.

High throughput synthesis of polyesters using entropically driven ring-opening polymerizations.

Copolyesters were synthesized in a high throughput (HT) manner and in high yield on ca. a 90 mg scale using entropically driven ring-opening polymerizations (ED-ROPs). This synthetic approach is a valuable addition to the HT polymer synthesis arsenal in that it allows condensation-type polymers with relatively large repeat units, such as those in poly(ethylene terephthalate) and poly(butylene terephthalate), to be obtained easily. The synthetic procedure involved taking mixtures of the appropriate macrocyclic oligoesters and heating them together under neat conditions at 250-300 degrees C for 2 h in the presence of 0.1 mol % of di- n-butyltin oxide or tetra- n-butylammonium tetrafluoroborate. In most cases Mw values were >25,000 and, as expected for ED-ROPs, the polydispersity indices were close to 2.0. Higher molecular weights could be obtained by using longer reaction times, but this might lead to product decomposition. The method worked well for esters formally derived from aliphatic or aromatic acids and alcohols, but less well for esters derived from phenols. Attempts were also made to synthesize copolymers by mixing together the two homopolymers and heating with a catalyst. These reactions were successful in a few instances, but generally, they were not. This is probably because the homopolymers did not mix well. An aluminum reaction block with 36 wells lined with Teflon cups, that fitted snugly in a cylindrical Buchi oven, was the most successful method for carrying out syntheses in an HT manner.

A bidentate terephthalamide ligand, TAMmeg, as an entry into terephthalamide-containing therapeutic iron chelating agents.

A new bidentate 2,3-dihydroxyterephthalamide ligand, 2,3-dihydroxy-N,N'-bis(2-methoxyethyl)terephthalamide (TAMmeg), has been prepared. The ligand, its synthetic precursor 2,3-bis(benzyloxy)-N,N'-bis(2-methoxy-ethyl)-terephthalamide (BnTAMmeg), and its iron complex have been structurally characterized by X-ray diffraction. BnTAMmeg crystallizes in the monoclinic space group P2(1)/n with cell parameters a = 14.4976(14) A, b = 11.5569(11) A, c = 16.3905(16) A, beta = 113.621(1) degrees , and Z = 4. TAMmeg crystallizes in the monoclinic space group P2(1)/c with cell parameters a = 13.8060(36) A, b = 8.0049(21) A, c = 19.4346(50) A, beta = 106.855(4) degrees , and Z = 4. Fe[TAMmeg] crystallizes in the triclinic space group P with cell parameters a = 12.9565(14) A, b = 13.4514(14) A, c = 20.2092(21) A, alpha = 102.093(2) degrees , beta = 95.433(2) degrees , gamma = 101.532(2) degrees , and Z = 2. The aqueous protonation and ferric ion coordination chemistry of TAMmeg were examined using potentiometric and spectrophotometric methods. Proton association constants and iron complex formation constants for the ligand are as follows: log beta(011) = 10.32, log beta(012) = 16.49, log beta(110) = 17.9, log beta(120) = 32.1, and log beta(130) = 43.0. The ferric complex of TAMmeg is surprisingly stable for a bidentate terephthalamide iron complex. The only more-stable bidentate terephthalamide iron complex that has been reported contains a ligand with positively charged pendant arms.

Polymerization and surface analysis of electrically-conductive polypyrrole on surface-activated polyester fabrics for biomedical applications.

A new synthetic route is reported for the synthesis and covalent bonding of electrically conductive polypyrrole to a poly(ethylene terephthalate) fabric. It involves a three-step process including surface phosphorylation and graft polymerization from the gaseous phase. In the first step, the fibre surfaces are activated using phosphorus trichloride. Then, 1-(3-hydroxypropyl) pyrrole is introduced and grafted to the phosphorus chloride to create an ester bond between the fibres and the pyrrole. Finally, the pyrrole-grafted fibres are dipped in an aqueous FeCl3 catalyst and exposed to pyrrole monomer vapor for the final polymerization. This last step creates an electrically conductive polypyrrole layer covalently linked to the poly(ethylene terephthalate) fibres. ESCA analysis indicates a high degree of phosphorylation and grafting of the anchor molecules. Scanning electron microscopy reveals an overall smooth and uniform surface coating of polypyrrole on the polyester fibres. The use of ATR-FTIR spectroscopy is not able to distinguish between polypyrrole-coated and non-coated fabrics because of the extremely thin polypyrrole layer. Measurements of dynamic surface wetting indicated that the polypyrrole-coated fabric is more hydrophilic than the untreated control. With values for surface resistivity in the range 10(4)-10(5) ohmz/square, such polypyrrole-coated fabrics are considered attractive candidates for biomedical applications.

Interference of therephthalic groups present in Dacron with spectrophotometric azide determination.

The determination of azide groups introduced into Dacron cannot be established by the method based on the Fe3+ - N3- complex because the therephthalic groups present in the polymer also react with Fe3+ to form a product with absorbance at 458 nm.

Interference of therephthalic groups present in dacron with spectrophotometric azide determination

The determination of azida groups introduced into Dacron cannot be established by the method based on the Fe + -N3 complex because the therephthalic groups present in the polymer also react with Fe + to form a product with absorbance at 458 nm

[Use of low-temperature plasma in the preparation of synthetic polymers for modification by collagen]. / Zastosowanie plazmy niskotemperaturowej w przygotowaniu polimerów syntetycznych do modyfikowania kolagenem.

The physico mechanical properties of films, vascular prostheses and nets made of polyethylene terephthalate and polyethylene film treated with the low temperature plasma were investigated. The plasma was generated by glow discharge in air under the following conditions: gas pressure - , current - 0.4-0.6 A, time of treatment - 40-240 s. stated that the angles of wetting with water and collagen solution of films treated with plasma decreases considerably. Sharp decreasing of wetting angles is followed by quick rise of the between water and polymeric film, and also by the increasing of free surface energy. The increasing of the wettability does not change during the storing time. The breaking stress and extension of the films treated with plasma are the same or a little bit higher than those of the untreated ones. The collagen modified by radiation shows high adhesion to the polymeric materials treated with plasma. The value of this adhesion 6 x 10(5) mN/m for polyester film, is about 6 times higher than the value of adhesion obtained by other authors, if the polyester film was treated with air plasma generated by spark discharge method.